1. Field of the Invention
The present invention relates to a modified aluminum oxy compound, a polymerization catalyst containing said modified aluminum oxy compound as a component, and a process for producing a polymer with said catalyst.
2. Description of the Related Arts
Many processes for producing an olefin polymer with a polymerization catalyst using a transition metal compound (for example, a metallocene and non-metallocene compound) and an aluminum oxy compound, are well-known. For example, a process using bis(cyclopentadienyl)zirconium dichloride and methylaluminoxane, is reported in JP58/019309A. However, in order to obtain the olefin polymer at a high yield, it is necessary to add a large amount of the aluminum oxy compound such as 1000 to 10000 moles of aluminum atom per 1 mole of transition metal atom. This has lead to major problems such as a high production cost and the residue of a large amount of aluminum atoms in the olefin polymer causes a bad influence on the properties of the olefin polymer.
In order to solve these problems, many reports concerning the reduction of the amount of aluminum oxy compound used have been made. For example, processes using a transition metal compound and a combination of an aluminum oxy compound and an organoaluminum compound are reported in JP60260602A and JP60130604A. Further, a process using methylaluminoxane and an aluminum oxy compound in which at least one isobutyl group is bonded with an aluminum atom, and a metallocene complex, and the like, are reported in JP63130601A. However, these processes do not reach a sufficient solution of the above-mentioned problems.
Further, polymers obtained with these catalysts have a low molecular weight in general, and the improvement has been further required for practical use.
A process using an aluminum oxy compound having an electron withdrawing group or an electron withdrawing group-containing group as an olefin polymerization catalyst component is recently reported in JP06329714A. According to this process, a highly active catalyst can be obtained, and an olefin polymer with a relatively high molecular weight can be obtained by polymerizing an olefin using said catalyst. However, the catalyst activity and the molecular weight of the olefin polymer obtained are not always sufficient, the invention of an aluminum oxy compound for realizing the more improvement of activity and the molecular weight of a polymer has been desired in order to produce an industrially useful olefin polymer.
Moreover, various investigations for synthesis of an xcex1-olefin polymer having stereoregularity using a metallocene complex have been further carried out, and a trial of synthesizing a highly stereoregular xcex1-olefin polymer by designing the structure of a metallocene complex is carried out.
For example, a production example of a highly stereoregular isotactic propylene polymer using a metallocene complex in which a methyl group is introduced at 2-position of the indenyl group of a silicon-bridging type bis(indenyl)complex and an isopropyl group, a phenyl group or a naphthyl group is introduced at 4-position (Organometallics 1994, 13, 954.), and a production example of a highly stereoregular isotactic propylene polymer using a metallocene complex in which two of mono- to tri-substituted xcex75-cyclopentadienyl groups are bridged (JP-B-258725, JP-B-2627669 and JP-B-2668732) are known.
Further, it is reported that a syndiotactic propylene polymer is obtained by using an aluminum oxy compound with isopropylidene(cyclopentadienyl) (fluorenyl)zirconium dichloride which is a metallocene complex having Cs symmetry, or the like (J.Am.Chem.Soc.,1988,110,6255.).
An object of the present invention is to provide a modified aluminum oxy compound that is useful as a component of an olefin polymerization catalyst, which catalyst is capable of producing a high molecular weight olefin polymer with a high efficiency, and is prepared by contacting a transition metal compound with the modified aluminum compound.
Another object of the present invention is to provide a highly active olefin polymerization catalyst component using said aluminum oxy compound.
Further, another object of the present invention is to provide a process for producing a high molecular weight olefin polymer with said polymerization catalyst.
Still further, another object of the present invention is to provide an alkenyl aromatic hydrocarbon copolymer of high molecular weight and a process for producing the same with said polymerization catalyst.
Moreover, another object of the present invention is to provide a catalyst for xcex1-olefin polymerization capable of producing a highly stereoregular xcex1-olefin polymer, and a process for producing a highly stereoregular xcex1-olefin polymer with said catalyst.
Other objects and advantages of the present invention will be apparent from the following description.
Namely, the present invention relates to a modified aluminum oxy compound, which has been modified with a compound having a hydroxy group, in which the ratio [M2/M1] of the intensity (M2) at 30 ppm to the intensity(M1) at 10 ppm of the spectrum in the 27Al-solid NMR is 0.60 or more; a polymerization catalyst component containing (A)said modified aluminum oxy compound; and an olefin polymerization catalyst obtained by a process that comprises contacting (A)said modified aluminum oxy compound, (B)a transition metal compound, and optionally (C)an organoaluminum compound or optionally (C)an organoaluminum compound and (D)a boron compound. Further, the present invention relates to a process for producing an olefin polymer which comprises homopolymerizing an olefin or copolymerizing olefins with said polymerization catalyst, and a process for producing an alkenyl aromatic hydrocarbon polymer which comprises homopolymerizing an alkenyl aromatic hydrocarbon or copolymerizing an alkenyl aromatic hydrocarbon and an olefin with said polymerization catalyst, and a copolymer of an alkenyl aromatic hydrocarbon and an olefin, having a number average molecular weight of 700,000 or more and a molecular weight distribution in terms of a ratio of weight average molecular weight(Mw) to number average molecular weight(Mn)[Mw/Mn] of 1.85 to 2.5.
Further, the present invention relates to a catalyst for xcex1-olefin polymerization obtained by contacting said modified aluminum oxy compound with (B) a transition metal compound having a capability of stereoregular polymerization of xcex1-olefin. Further, the present invention relates to a process for producing a stereoregular xcex1-olefin polymer using said catalyst.